QUANTUM-TO-CLASSICAL TRANSITION FOR FLUCTUATIONS IN THE EARLY UNIVERSE
QUANTUM-TO-CLASSICAL TRANSITION FOR FLUCTUATIONS IN THE EARLY UNIVERSE
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DOI：
10.1142/s0218271898000292
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发表时间：
1998-02
影响因子：
2.2
通讯作者：
C. Kiefer;D. Polarski;A. Starobinsky
中科院分区：
文献类型：
--
作者：
C. Kiefer;D. Polarski;A. Starobinsky
根据宇宙非常早期的膨胀假说，宇宙中所有的不均匀都是真正的量子起源。另一方面，观察这些不均匀性并对它们进行测量，显然没有观察到特定的量子力学性质。我们展示了从它们固有的量子引力性质到经典行为的转变是如何发生的--在这种转变中，对当今宇宙的通胀情景的成功定量预测都没有改变。这是由两个属性实现的。首先，由于宇宙的膨胀(只要扰动的波长超过哈勃半径)，早期宇宙中由量子引力效应产生的时空度规微扰的量子态变得非常特殊(高度压缩)。其次，通过环境的退相干将场幅度基准区分为指针基准。这使得目前的微扰无法与随机经典不均匀区分开来。
According to the inflationary scenario for the very early Universe, all inhomogeneities in the Universe are of genuine quantum origin. On the other hand, looking at these inhomogeneities and measuring them, clearly no specific quantum mechanical properties are observed. We show how the transition from their inherent quantum gravitational nature to classical behavior comes about — a transition whereby none of the successful quantitative predictions of the inflationary scenario for the present-day universe is changed. This is made possible by two properties. First, the quantum state for the spacetime metric perturbations produced by quantum gravitational effects in the early Universe becomes very special (highly squeezed) as a result of the expansion of the Universe (as long as the wavelength of the perturbations exceeds the Hubble radius). Second, decoherence through the environment distinguishes the field amplitude basis as being the pointer basis. This renders the perturbations presently indistinguishable from stochastic classical inhomogeneities.